!! Read the comments !!
The second image displays my rail "launcher", which is a single powered rail that is activated by a button, and pushes the cart towards a series of powered rails, powered by a Redstone Block each.
Once I reach the End Gateway, it seems I'm stuck in it. I can still hear the rail cart going, but I can't see anything but the SkyTexture. I run "/tp ~ ~1 ~" and it confirms I was not teleported back to the main island, and everything is "derendered" as you can see in the first image. Even the Endermen aren't visible from roughly 8 blocks away.
Duplicate of MC-97701?